1. Field of the Invention
The invention relates to optical signal transmission. More particularly, the invention relates to an apparatus and method for steering or redirecting light beams within optical communications systems.
2. Description of the Related Art
Redirecting or steering an optical signal or beam within an optical communications system is accomplished by many conventional devices and for many different reasons. Often, optical signals are redirected to better align them with one or more components within the system. For example, optical signals often are redirected to better align with a detector or receiver after having passed through various system components. Also, because optical sources such as an edge or surface emitting laser or a light emitting diode (LED) and optical detectors such as semiconductor photodetectors and photodiodes often are oriented differently with respect to the path of light travel into or out of the particular device or package, optical beams often must be redirected for better alignment therewith.
Also, in many optical communications systems, optical sources and detectors are packaged together as part of a transceiver or as part of multiple source/detector arrangements. In a typical transceiver configuration, the optical source and its corresponding detector often are side by side, with the distance between respective central axes thereof on the order of 5 millimeters (mm). In a typical optical communications system arrangement, at least a portion of an optical signal transmitted from an optical source of a first transceiver is transported to various system components including an optical receiver or detector from, e.g., a second transceiver, while another optical signal is transported from a source of the second transceiver to, e.g., the optical receiver/detector of the first transceiver.
Conventional beam steering devices include devices that actively change the direction of transmitted or reflected beams using, e.g., movable lens or mirror arrangements. Such active beam steering devices include, e.g., U.S. Pat. Nos. 4,961,627 and 5,600,741. However, active beam steering devices often are relatively expensive and bulky, as they typically require some mechanical means for providing translational or rotational motion to the lenses, mirrors and/or prisms. Such devices typically are geared toward applications that require relatively precise alignment tolerances.
Conventional beam steering devices also include passive devices, such as substrates with grooves and reflective surfaces formed therein for aligning, e.g., optical fibers and other waveguide structures for steering beams. See, e.g., U.S. Pat. No. 5,073,003, which is assigned to the assignee of this application, and U.S. Pat. No. 5,600,741.
Although many conventional devices and techniques exist for actively and passively steering beams of optical signal through optical communications systems, it is desirable to have available a relatively simple, efficient and inexpensive apparatus and method for passively redirecting optical beams. Also, it is desirable to have available a passive beam steering device with the flexibility to be useful in many different beam steering applications.